WO2018038404A1 - Method for manufacturing epoxy reactive diluent - Google Patents

Abstract

The present invention relates to a method for manufacturing an epoxy reactive diluent which minimizes the amount of epichlorohydrin that is removed in an addition reaction of a branched monocarboxylic acid and epichlorohydrin and a process time and does not use a separate nonpolar solvent in the neutralization process, thereby capable of increasing productivity and improving quality issues.

Description

Process for preparing epoxy reactive diluent

The present invention relates to a process for preparing an epoxy reactive diluent.

Epoxy-reactive diluents, especially branched monocarboxylic acid-modified epoxy reactive diluents, are primary addition reactions in which epichlorohydrin is added to branched monocarboxylic acids in the presence of a metal ammonium catalyst and hydrolyzable in the primary addition polymerization product. The chlorine powder structure can be obtained by secondary epoxy ring-closure reaction which is closed by an alkali metal catalyst, that is, caustic soda to form an epoxy functional group. The detailed reaction mechanism is as follows.

[Reaction Mechanism in Preparation of Branched Monocarboxylic Acid-Modified Epoxy Reactive Diluent]

Primary addition reaction: addition bond of branched monocarboxylic acid and epichlorohydrin

2nd epoxy ring closure

(In the formula, R1, R2 and R3 are organic groups such as alkyl group.)

However, when the caustic soda used as a catalyst in each reaction step of the above mechanism is added in an aqueous state, hydrolysis proceeds as follows by water in the caustic soda solution and reaction condensation water generated during the secondary epoxy ring closure reaction. Hydrolysis residues are generated as the decomposition progresses, and problems of epoxy equivalent increase, side reactant content increase, and viscosity increase are caused by re-participation of the reaction of the hydrolysis residue. This hydrolysis mechanism is as follows.

Hydrolysis Reaction Mechanism

Hydrolysis of the reaction intermediate

Hydrolysis of the Final Composite

(In the formula, R1, R2 and R3 are organic groups such as alkyl group.)

When the above hydrolysis products are generated, a large amount of side reactions occur due to the properties of the epoxy functional groups exhibiting strong reactivity under strong alkali conditions, resulting in problems such as lowering purity, lower functional group content, higher viscosity, and color change. .

Korean Patent Publication No. 10-2012-0016313 discloses a method for preparing a branched monocarboxylic acid glycidyl ester by adding 1.4-1.6 times moles of metal hydroxide relative to monocarboxylic acid in a ring closing reaction (epoxy cyclization). Is disclosed. However, when an excess amount of metal hydroxide, a strong alkaline substance, is added in the presence of the water generated during the ring closure reaction, hydrolysis and side reactions are promoted, such that the epoxy functional group content decreases due to the decrease in purity, the viscosity rises, discoloration, etc. May cause problems.

The present invention minimizes the amount and process time of epichlorohydrin removed in the addition reaction of branched monocarboxylic acid and epichlorohydrin, and increases productivity by not using a separate nonpolar solvent in the neutralization process, An object of the present invention is to provide a method for preparing an epoxy reactive diluent which can improve quality problems.

The process for producing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention comprises the steps of: (1) adding a branched monocarboxylic acid and epichlorohydrin in the presence of a catalyst; (2) performing an epoxy ring closure of the addition reaction product of step (1) while azeotropic epichlorohydrin with water and refluxing epichlorohydrin in the presence of metal hydroxide and under reduced pressure; (3) removing unreacted epichlorohydrin from the resultant mixture of step (2); (4) adding a metal hydroxide to the resultant of step (3), stirring, and then separating the layers to collect the upper organic layer; And (5) adding water to the organic layer collected as a result of step (4), stirring, and separating the upper organic layer by layer separation, wherein the monocarboxylic acid and epichlorohydrin of step (1) are used. The molar ratio of 1: 1.5 to 1: 2.5, and in step (5) does not add a separate non-polar organic solvent.

According to the present invention, epichlorohydrin and organic solvent are minimized by minimizing the amount of epichlorohydrin used in the addition reaction of monocarboxylic acid and epichlorohydrin, and by not using a separate nonpolar organic solvent in the neutralization process. The branched monocarboxylic acid-modified reactive epoxy of high purity can be produced, improving the problems, such as a quality problem and energy loss which arise in a removal process.

Hereinafter, the present invention will be described in more detail.

In step (1) of the method for preparing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, the branched monocarboxylic acid and epichlorohydrin are added and reacted in the presence of a catalyst.

The catalyst usable in step (1) may include a metal ammonium catalyst such as tetramethylammonium chloride, tetraethylammonium chloride, alkali metal catalyst such as sodium hydroxide, potassium hydroxide, and the like, but is not limited thereto. It may be used without limitation as long as it is a known catalyst known to be usable for the addition reaction of carboxylic acid and epichlorohydrin. There is no particular limitation on the amount of the catalyst, and for example, 0.01 to 1 part by weight of the catalyst may be used based on 100 parts by weight of the total amount of the reactant branched monocarboxylic acid and epichlorohydrin.

Examples of the branched monocarboxylic acid usable in step (1) include branched alkanoic monocarboxylic acids having 3 to 20 carbon atoms, for example, having 5 to 15 carbon atoms. For example, neodecanoic acid, 2-ethylhexanoic acid, and the like, but are not limited thereto, and may be used without limitation as long as it can react with epichlorohydrin to form a modified epoxy reactive diluent.

The molar ratio of the branched monocarboxylic acid and epichlorohydrin used in step (1) may be 1: 1.5 to 1: 2.5 of branched monocarboxylic acid: epichlorohydrin in a molar ratio, for example, 1: 1.6 to 1: 2.4. If the amount of epichlorohydrin compared to the branched monocarboxylic acid is too small than the molar ratio range, there may be a problem that the molecular weight increase and the epoxy equivalent due to side reactions are increased, and if the amount of epichlorohydrin is excessively larger than the molar ratio range, It takes a long time to remove the unreacted epichlorohydrin, and a large amount of water-soluble side reactions are generated so that separation of the aqueous layer and the organic layer is not desired. Therefore, a separate nonpolar organic solvent such as toluene should be used in the subsequent step (5). There may be a problem.

The addition reaction conditions of the branched monocarboxylic acid and epichlorohydrin in step (1) is not particularly limited, and known reaction conditions may be used as they are or as appropriately modified. For example, the reaction of step (1) may be performed at 70 to 100 ° C. (eg, 80 to 90 ° C.) for 1 to 4 hours (eg, 1.5 to 3 hours) at normal pressure, but is not limited thereto.

In step (2) of the method for preparing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, in the presence of a metal hydroxide and under reduced pressure, azeotropes epichlorohydrin with water to reflux epichlorohydrin. While performing the epoxy ring closure of the addition reaction product of step (1).

Examples of metal hydroxides that can be used as catalysts in the step (2) include caustic soda (sodium hydroxide), potassium hydroxide, and the like, but are not limited thereto. It can be used without limitation. There is no particular limitation on the amount of metal hydroxide used in step (2), and branched monocarboxylic acid: metal hydroxide may be 1: 0.9 to 1: 1.1 in molar ratio, for example, 1: 0.95 to 1: 1.05. Can be.

As the reduced pressure condition of the step (2), the pressure in the reactor may be 100 to 200 torr, for example, 120 to 180 torr, for example 130 to 170 torr. (2) If the pressure condition of the step reaction is less than 100torr, there may be a problem that the reflux process is not smooth due to the excessive outflow of the reactant and residual epichlorohydrin, and if it exceeds 200torr effectively removes the water remaining in the reaction system Failure to do so may cause problems such as hydrolysis and side reactions caused by residual moisture.

The temperature condition of the reaction of step (2) may be 50-70 ° C, for example 60-65 ° C. If the temperature of the step (2) reaction is less than 50 ℃ may have a problem that the epoxy ring-closure reaction is not performed smoothly, if it exceeds 70 ℃ may have a problem of the molecular weight and epoxy equivalent rise by the side reaction occurs.

In the existing processes, the ring-closure reaction was performed while leaving the water generated during the epoxy ring-closure reaction corresponding to step (2) in the reaction system, but in the present invention, the reduced pressure during the ring-closure reaction was performed to reduce the water generated during the reaction. Remove the reaction and proceed with the reaction. In more detail, if the inside of the reactor is maintained at a constant temperature and a reduced pressure, azeotropic distillation may occur due to reduced pressure, and the effluent discharged from the azeotropic distillation may flow out of a mixture of water and excess epichlorohydrin. The effluent is transferred to the separation tank and phase separated into water and epichlorohydrin due to the specific gravity difference, so that the relatively large epichlorohydrin is collected in the lower phase of the phase separation. Epichlorohydrin thus collected is re-injected into the reaction tank to maintain a constant epichlorohydrin concentration in the reaction system. When water is removed using the reduced pressure azeotropic distillation, water can be effectively removed even at a temperature less than 100 ° C required to remove water at normal pressure, thereby preventing hydrolysis due to residual water and side reactions due to high temperature. There is a prevention effect, and side reaction between the reaction products can be prevented by keeping the concentration of epichlorohydrin in the reaction system constant.

In step (3) of the method for preparing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, unreacted epichlorohydrin is removed from the resultant mixture of step (2). The removal of epichlorohydrin can be carried out under elevated temperature and reduced pressure conditions, for example after completion of the reaction of step (2) the resulting mixture is heated to 110-140 ° C. (eg 120-130 ° C.) and the degree of pressure reduction in the reactor is stepwise. The residual epichlorohydrin can be removed by maintaining the pressure at a final 80 to 110 torr, such as 90 to 100 torr. If the pressure is lower than the numerical range, the epoxy equivalent of the final resin may be high due to the loss of the low molecular weight material. If the pressure is higher than the numerical value, the pressure may not be sufficiently removed or the efficiency of the process may be reduced.

In step (4) of the method for preparing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, metal hydroxide is added to the resultant of step (3), stirred, and the layers are separated to collect the upper organic layer. .

Examples of the metal hydroxide that can be used in the step (4) include caustic soda (sodium hydroxide), potassium hydroxide, and the like, but are not limited thereto. Can be used. There is no particular limitation on the amount of metal hydroxide used in step (4), for example, 0.1-2 parts by weight (for example, 0.5-2 parts by weight) based on 100 parts by weight of the total amount of the branched monocarboxylic acid and epichlorohydrin as reactants. Metal hydroxides of may be used.

The temperature condition of step (4) is 60-100 ℃, for example, may be 65-95 ℃. In addition, after addition of the metal hydroxide to the resultant of step (4) to (3), the stirring may be performed for 1 to 3 hours. In addition, an appropriate amount of water may be added for layer separation after stirring.

The result of the completion of the epoxy ring closure and the removal of unreacted epichlorohydrin contains a significant amount (eg, about 10,000 ppm) of hydrolyzed chlorine, in addition to a small amount of side reactions. When the hydrolyzed chlorine content and a small amount of side reactions remain, the use of the diluent of the present invention in paints applied to metal deposits may cause problems of corrosion resistance and water resistance, and in addition, the above-mentioned purity decrease and side effects may occur. have. In the present invention, through the step (4), the ring-closure reaction of the residual hydrolyzable chlorine may be further progressed, and the minor residual reactants may be easily reacted to precipitate and then removed.

In step (5) of the method for preparing a branched monocarboxylic acid-modified epoxy reactive diluent of the present invention, water is added to the organic layer collected as a result of step (4), stirred, and the layers are separated to collect the upper organic layer. . At this time, by not adding a separate non-polar organic solvent, it is possible to omit the step of removing the high temperature and reduced pressure conditions for the removal of the non-polar organic solvent.

There is no particular limitation on the amount of water used in step (5), for example, 15 to 30 parts by weight of water may be used based on 100 parts by weight of the total amount of the branched monocarboxylic acid and epichlorohydrin as reactants.

Preferably in step (5), the acid may be further added to the organic layer of step (4). The additionally charged acid is removed by agglomeration and precipitation of ionic impurities from the organic layer of step (4). The acid usable in step (5) may include an organic acid, an inorganic acid, or a combination thereof, and for example, one selected from acetic acid, phosphoric acid, and a combination thereof may be used. There is no particular restriction on the amount of such acid, and for example, 0.01 to 2 parts by weight (for example, 0.02 to 0.5 parts by weight) of acid may be used based on 100 parts by weight of the total amount of the branched monocarboxylic acid and epichlorohydrin as reactants.

In the step (5), after the water is added to the organic layer of step (4) and stirred, the temperature conditions of the process of layer separation may be 60-100 ℃, for example 65-95 ℃.

According to the present invention, a high purity epoxy reactive diluent having an epoxy equivalent (g / eq) of 235-245eq, a hydrolyzable chlorine content of 400 ppm or less, and a total chlorine content of 900 ppm or less can be prepared.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only intended to help the understanding of the present invention, but the scope of the present invention in any sense is not limited to the examples.

Example  One

(1) Into a 2-liter flask equipped with a stirring device, a thermometer, a nitrogen inlet tube, a separation reflux tube, and a condenser, 384 g of neodecanoic acid and 464 g of epichlorohydrin were added thereto, and the temperature was raised to 60 ± 2 ° C. . After completion of the temperature increase, 9.6 g of tetramethylammonium chloride 50% aqueous solution was added thereto, and the temperature was raised to 80-90 ° C. by spontaneous heating and maintained for 2 ± 0.5 hours.

(2) After that, while maintaining the reactor temperature at 63 ± 2 ° C. and reducing the pressure inside the reactor to 150 ± 30 torr, 178.4 g of caustic soda 50% aqueous solution was uniformly added for 2 ± 0.5 hours, and the reaction was refluxed. Epoxy ring closure was performed under the following conditions. The effluent flowing into the separation reflux tube during the reaction was separated into water and epichlorohydrin through phase separation, and the collected epichlorohydrin was re-introduced into the reactor.

(3) After the addition of a 50% aqueous solution of caustic soda, the temperature was raised to 130 ± 5 ° C. under reduced pressure, and after completion of the temperature increase of 130 ± 5 ° C., 1 ± 0.5 hours at 150torr and 1 ± 0.5 hours at 100torr. Was removed.

(4) After epichlorohydrin was removed, the resultant was cooled to 95 ± 2 ° C., and then maintained for 80 ± 20 minutes after adding 14.7 g of water and 9.8 g of 50% aqueous solution of caustic soda. Thereafter, 460 g of water was added and stirred at 70 ± 5 ° C. for 30 minutes to dissolve salts generated during the reaction. Thereafter, the contents were transferred to a separatory funnel, held for 30 minutes, phase separated into an upper organic layer and a lower brine layer, and the lower brine layer was removed.

(5) After the upper organic layer was transferred to a flask, 270 g of water and 0.5 g of phosphoric acid were added thereto, stirred at 70 ± 5 ° C. for 30 minutes, and then the contents were transferred to a separatory funnel and held for 30 minutes. After removing the lower aqueous layer in the same manner as before, a branched monocarboxylic acid-modified reactive epoxy diluent was prepared.

The epoxy equivalent (EEW) of the branched monocarboxylic acid-modified reactive epoxy diluent thus prepared was 239 g / eq, the hydrolyzable chlorine content was 110 ppm, and the total chlorine content was 608 ppm.

Example  2

In the step (1) of Example 1, 392 g of epichlorohydrin was added, and in step (4), the same procedure as in Example 1 was carried out except that 7.7 g of 50% caustic soda solution was added. Acid-modified reactive epoxy diluents were prepared. The epoxy equivalent (EEW) of the resultant product was 240 g / eq, the hydrolyzable chlorine content was 210 ppm, and the total chlorine content was 705 ppm.

Example  3

In step (1) of Example 1, 351 g of epichlorohydrin was added, and in step (3), after completion of temperature rise of 130 ± 5 ° C., 1 ± 0.5 hours at 150torr and 1 ± 0.5 hours at 105torr, A branched monocarboxylic acid-modified reactive epoxy diluent was prepared in the same manner as in Example 1 except that 6.3 g of 50% aqueous sodium hydroxide solution was added in step (4). Thus obtained epoxy equivalent (EEW) was 241g / eq, hydrolyzable chlorine content was 310ppm, total chlorine content was 810ppm.

Example  4

In step (1) of Example 1, 310 g of epichlorohydrin was added, and in step (3), after completion of the temperature rise of 130 ± 5 ° C., 1 ± 0.5 hour at 150torr and 1 ± 0.5 hour at 110torr, A branched monocarboxylic acid-modified reactive epoxy diluent was prepared in the same manner as in Example 1, except that 4.2 g of 50% aqueous caustic soda solution was added in step (4). The resulting epoxy equivalent (EEW) was 241 g / eq, the hydrolyzable chlorine content was 350 ppm, and the total chlorine content was 854 ppm.

Example  5

In step (1) of Example 1, 516 g of epichlorohydrin was added, and in step (3), after completion of the temperature rise of 130 ± 5 ° C, 1 ± 0.5 hours at 150torr and 1 ± 0.5 hours at 80torr, the remaining epichlorohydrin The branched monocarboxylic acid-modified reactive epoxy diluent was prepared in the same manner as in Example 1, except that 12.9 g of 50% aqueous caustic soda solution was added in step (4). The epoxy equivalent (EEW) of the resultant product was 240 g / eq, the hydrolyzable chlorine content was 110 ppm, and the total chlorine content was 608 ppm.

Comparative example  One

(1) Into a 2-liter flask equipped with a stirrer, thermometer, nitrogen inlet tube, separation reflux tube, and condenser, 384 g of neodecanoic acid and 618.8 g of epichlorohydrin were added and the temperature was raised to 60 ± 2 ° C. It was. After completion of the temperature increase, 9.6 g of tetramethylammonium chloride 50% aqueous solution was added thereto, and the temperature was raised to 80-90 ° C. by spontaneous heating and maintained for 2 ± 0.5 hours.

(2) After that, while maintaining the reactor temperature at 63 ± 2 ° C. and reducing the pressure inside the reactor to 150 ± 30 torr, 178.4 g of caustic soda 50% aqueous solution was uniformly added for 2 ± 0.5 hours, and the reaction was refluxed. Epoxy ring closure was performed under the following conditions. The effluent flowing into the separation reflux tube during the reaction was separated into water and epichlorohydrin through phase separation, and the collected epichlorohydrin was re-introduced into the reactor.

(3) After the 50% aqueous solution of caustic soda was added, the temperature was raised to 125 ± 5 ° C. under reduced pressure, and after the completion of the temperature rising to 125 ± 5 ° C., the pressure was gradually reduced to less than 10 torr to remove residual epichlorohydrin It was.

(4) After the completion of epichlorohydrin removal, the resultant was cooled to 90 ± 5 ° C., and then maintained for 80 ± 20 minutes after adding 14.7 g of water and 17.3 g of 50% caustic soda solution. Thereafter, 460 g of water was added and stirred at 70 ± 5 ° C. for 30 minutes to dissolve salts generated during the reaction. Thereafter, the contents were transferred to a separatory funnel, held for 30 minutes, phase separated into an upper organic layer and a lower brine layer, and the lower brine layer was removed.

(5) After transferring the upper organic layer to the flask, 125 g of toluene, 270 g of water, 0.5 g of phosphoric acid was added thereto, and stirred at 70 ± 5 ° C. for 30 minutes, and then the contents were transferred to a separatory funnel for 30 minutes. Maintained. After removing the lower aqueous layer in the same manner as before, the upper organic layer was transferred to a flask, and heated to 130 ° C to remove toluene first, and then toluene was further removed by reducing the pressure to less than 100 torr to obtain a branched monocarboxylic acid-modified reactive epoxy diluent. Prepared.

The epoxy equivalent (EEW) of the branched monocarboxylic acid-modified reactive epoxy diluent thus prepared was 240.7 g / eq, the hydrolyzable chlorine content was 112 ppm, and the total chlorine content was 811 ppm.

Comparative example  2

In step (3) of Example 2, the reaction was performed in the same manner as in Example 2 except that 1 ± 0.5 hours at 150torr and 1 ± 0.5 hours at 70torr after completion of the temperature increase at 130 ± 5 ° C. Topographic monocarboxylic acid modified reactive epoxy diluents were prepared. Thus obtained epoxy equivalent (EEW) was 246g / eq, hydrolyzable chlorine content was 220ppm, total chlorine content was 715ppm.

Comparative example  3

In step (3) of Example 2, the reaction was performed in the same manner as in Example 2 except that 1 ± 0.5 hours at 150torr and 1 ± 0.5 hours at 120torr after removal of the temperature of 130 ± 5 ° C. Topographic monocarboxylic acid modified reactive epoxy diluents were prepared. The resulting epoxy equivalent (EEW) was 244 g / eq, the hydrolyzable chlorine content was 1,256 ppm and the total chlorine content was 1,843 ppm.

Comparative example  4

A branched monocarboxylic acid-modified reactive epoxy diluent was prepared in the same manner as in Example 2, except that 34.2 g of a 50% caustic soda solution was added in step (4) of Example 2. Thus obtained epoxy equivalent (EEW) was 247g / eq, the hydrolyzable chlorine content was 250ppm, the total chlorine content was 873ppm.

The present invention minimizes the amount and process time of epichlorohydrin removed in the addition reaction of branched monocarboxylic acid and epichlorohydrin, and increases productivity by not using a separate nonpolar solvent in the neutralization process, Provided is a method for preparing an epoxy reactive diluent that can improve quality problems.

Claims (10)

1. (1) addition reaction of branched monocarboxylic acid and epichlorohydrin in the presence of a catalyst;

   (2) performing an epoxy ring closure of the addition reaction product of step (1) while azeotropic epichlorohydrin with water and refluxing epichlorohydrin in the presence of metal hydroxide and under reduced pressure;

   (3) removing unreacted epichlorohydrin from the resultant mixture of step (2);

   (4) adding a metal hydroxide to the resultant of step (3), stirring, and then separating the layers to collect the upper organic layer; And

   (5) adding water to the collected organic layer as a result of step (4) and stirring, and then separating the layers to collect the upper organic layer.

   Including,

   The molar ratio of the monocarboxylic acid and epichlorohydrin of step (1) is 1: 1.5 to 1: 2.5,

   In step (5), do not add a separate non-polar organic solvent,

   Process for preparing branched monocarboxylic acid-modified epoxy reactive diluents.
2. The method for producing a branched monocarboxylic acid-modified epoxy reactive diluent according to claim 1, wherein the branched monocarboxylic acid is a branched alkanoic monocarboxylic acid having 3 to 20 carbon atoms.
3. The process for producing a branched monocarboxylic acid modified epoxy reactive diluent according to claim 1, wherein the metal hydroxide is caustic soda.
4. The method of claim 1, wherein the reaction of step (2) is carried out under a pressure of 100-200 torr.
5. The method of claim 1, wherein the reaction of step (2) is carried out at a temperature of 50-70 ℃.
6. The branched monocarboxyl according to claim 1, wherein the metal hydroxide is used in the step (4) in an amount of 0.1 to 2.0 parts by weight based on 100 parts by weight of the total of the branched monocarboxylic acid and epichlorohydrin. Process for preparing acid-modified epoxy reactive diluent.
7. The method of claim 1, wherein step (4) is carried out at a temperature of 60-100 ℃.
8. The branched monocarboxylic acid-modified epoxy according to claim 1, wherein water is added in an amount of 15-30 parts by weight based on 100 parts by weight of the total amount of the branched monocarboxylic acid and epichlorohydrin in step (5). Method for preparing a reactive diluent.
9. The method according to claim 1, wherein an acid is further added in step (5).
10. 10. The method of claim 9, wherein the acid is selected from acetic acid, phosphoric acid and combinations thereof.